I have UK visitor visa, so that part is sorted. I was confused about Ireland. Checked TIMATIC website and it looks like I should not need any visa, assuming that arrive at and depart are terminal 2 as per below quote.
I just checked time also, it reaches at 11:45 AM and leave for onwards at 3:20 PM.
TWOV (Transit Without Visa):
Passengers transiting through Dublin (DUB) with a confirmed onward ticket for a flight to a third country. They must:
- arrive at and depart from Terminal 2, and
- be transiting between 04:00 and 16:00 on the same calendar day, and
- stay in the international transit area of the airport, and
- have documents required for the next destination.